Can't Access to Login Screen

Today when I wanted to login to my dashboard and entered mywebsite.com/wp-admin/ , the underconstruction page appeared which usually should only appear for the website pages and not the admin. So after some reading on the web, I delete the underconstruction plugin via FTP. But I still can’t get the login screen when I want to, rather it is redirecting me another page of my website. Thus my website is working but the login page for my dashboard doesn’t. Please help. I have tried a number of ways to get it back.